Biomedical subjects

S J Tsai

Publications and source records attributed to S J Tsai.

At least 19 recordsLinked to original sources

PubMed2006

Expression of sex-determining genes in human sebaceous glands and their possible role in the pathogenesis of acne.

BACKGROUND: The human skin, especially the sebaceous gland, is a steroidogenic organ similar to the gonads and adrenal cortex, possessing all the enzymes required for steroid sex-hormone synthesis and metabolism. Factors regulating cutaneous steroidogenesis associated with disease status remain largely unknown. OBJECTIVE: We hypothesized that transcription factors involved in sex formation and regulation of steroidogenesis in the classical steroidogenic organs are also expressed in the sebaceous glands. Their possible role in the pathogenesis of acne were investigated. METHODS: We used reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization and Western blotting to analyse the expression of SF-1, WT-1, SRY, SOX-9 and DAX-1 mRNAs and their proteins in cultured human sebocytes and the facial skin of acne patients. RESULTS: The in situ hybridization study showed SOX-9 mRNA mainly localized in basal keratinocytes, the basal layer of the sebaceous glands and eccrine glands. Immortalized human sebaceous gland cells (SZ95) expressed mRNA for SOX-9, WT-1 and DAX-1 but not for SF-1 or SRY. The expression of DAX-1 protein was slightly inhibited by 10(-6) m oestradiol (E2) at 6 h but enhanced by 10(-6) m dihydrotestosterone (DHT) at 48 h. The facial expression of SOX-9 seemed to be higher in the acne-prone male patients, while DAX-1 was stronger in subjects without acne, although both were statistically insignificant. CONCLUSION: Our findings confirm the expression of some sex-determining genes in human sebaceous glands. Further studies on a larger patient population including the normal controls are needed to elucidate the functional significance of these transcription factors in the pathogenesis of acne.

Acne Vulgaris↗

PubMed2003

Acute reduction in serum progesterone concentrations after feed intake in dairy cows.

This study tested the hypothesis that high feed consumption will acutely decrease circulating progesterone concentrations. In the first experiment, a Latin Square design was used to test whether feeding pattern would alter circulating progesterone in pregnant lactating Holstein cows (n = 12). Feed was removed for 12h before the experiment and cows were then either fed 100% of the total mixed ration (TMR), 50% of TMR every 12h, 25% of TMR every 6h, or left unfed for an additional 12h. Blood samples were taken every hour for 24h. Provision of 100 or 50% of TMR decreased circulating progesterone by 1h after feeding and progesterone remained depressed until 8-9h after feeding. Feeding 25% of TMR did not reduce circulating progesterone concentrations. Experiment 2 used a crossover design to measure the effect of acute feeding on circulating progesterone and LH concentrations during delivery of a constant amount of exogenous progesterone (Eazi-Breed CIDRs) in lactating Holstein cows (n = 8) and nonpregnant dry Holstein cows (n = 6). Blood samples were taken every 15min for 8h. There was no change in serum progesterone during the 8h treatment period in unfed cows; however, feeding decreased (P<0.05) circulating progesterone between 2 and 6h after feeding. In lactating cows, feeding increased mean LH (P<0.05). There were more LH pulses (P = 0.01) in lactating than nonlactating cows. Thus, acute feeding reduced circulating progesterone in pregnant lactating cows apparently due to an increase in progesterone metabolism. Interestingly, feeding multiple smaller meals eliminated the acute effect of feeding on circulating progesterone.

Animals↗

PubMed2003

Association study of the dopamine and serotonin transporter genetic polymorphisms and methamphetamine abuse in Chinese males.

The dopamine transporter (DAT) and the serotonin transporter (5-HTT) play important roles in methamphetamine (METH) dependence because they are the target of METH action. For this study, the association between the DAT and 5-HTT polymorphisms and METH dependence were investigated for a Chinese-male sample population. The investigated polymorphisms included those of the DAT 3'-variable number tandem repeat, the 5-HTT gene promoter and a 5-HTT variable number tandem repeat polymorphisms. No significant difference was demonstrated for genotype or allele frequency, when comparing METH dependent and control cases for the DAT and the 5-HTT polymorphisms. The findings of this study suggest that these polymorphisms do not play major roles in METH dependence in the Chinese-male population.

Adult↗

PubMed2003

The recovery of some components of the renin angiotensin system in the rat pancreas after chronic exposure to hypoxic condition.

Previous studies have shown that the expression of the major components from a local pancreatic renin-angiotensin system (RAS) was upregulated after chronic exposure to oxygen deprivation (10% oxygen). In the present study, the reversibility of expression for the pancreatic RAS affected by chronic hypoxia was investigated in the pancreas. Rats were first subject to hypoxia for one Month and they were then returned to normoxic conditions for a varying period of time (1, 2, 3 and 4 weeks). The degree of recovery in the expression of RAS components was analyzed with standard curve-quantitative competitive-reverse transcription-polymerase chain reaction (SC-QC-RT-PCR), Western blot analysis and a specific assay for angiotensin-converting enzyme (ACE) activity. Results from SC-QC-RT-PCR showed that the upregulated expression of angiotensin II type 1 (AT(1)) receptor mRNA following chronic hypoxia could be completely restored to the control level after the rats were returned to the normoxic condition for 3 weeks. The reversibility of mRNA expression for angiotensin II type 2 (AT(2)) receptor and angiotensinogen was observed after the return to normoxic conditions for 2 and 3 weeks respectively when compared with that of their respective controls. Results from Western blot analysis further confirmed that the expression of AT(1) receptor protein was also reversible after return to normoxic conditions for 4 weeks. In addition, the activation of ACE activity returned to its normal level in a time-dependent manner. These data indicate that the upregulation of a local pancreatic RAS affected by chronic hypoxia could be recoverable. The significance of its reversibility and adaptability following chronic hypoxia may be of physiological relevance to the pancreas.

Angiotensin II↗

PubMed2002

Regulation of progesterone and prostaglandin F2alpha production in the CL.

After the luteinizing hormone (LH) surge, the cells that remain from the ovulated follicle undergo a process of differentiation termed luteinization. Two key features of the cells after luteinization are the capacity for tremendous production of progesterone [10(16) molecules of progesterone per (min/(g of CL))] and the capacity to undergo regression or death of the cells at the appropriate time. There are two steroidogenic cell types, the small and large luteal cells that are regulated by different mechanisms. In small luteal cells, production of progesterone is stimulated by LH through the protein kinase A (PKA) pathway. The large luteal cells of ruminants produce large quantities of progesterone that is independent of LH stimulation. Although luteotrophins clearly regulate luteal function, much of luteal progesterone production in some species appears to be constitutive, consistent with the autonomous aspects of the large luteal cell. The key regulated step in luteal progesterone production appears to be regulation of transport of cholesterol to the inner mitochondrial membrane apparently mediated by the steroidogenic acute regulatory protein (StAR). In addition, our recent research indicates that PKA is tonically active in large luteal cells and this may be responsible for the high, relatively autonomous nature of luteal progesterone production. Regression of the corpus luteum (CL) in many species is initiated by prostaglandin (PG) F2alpha secreted from the uterus. Luteal cells also have the capacity for production of PGF2alpha. Luteal PGF2alpha production can be regulated by a variety of substances including inhibition by progesterone and stimulation by cytokines. We have also characterized a positive feedback pathway in ruminant and porcine CL in which small amounts of uterine PGF(2alpha) stimulate intraluteal production of PGF2alpha due to induction of the cycloxygenase-2 (Cox-2) enzyme in large luteal cells. This positive feedback pathway is only present in CL that has acquired the capacity for luteal regression ( approximately day 7 in cow, approximately day 13 in pig). Regulation by protein kinase C (PKC) of transcriptional factors interacting with an E-box in the 5' flanking region of the Cox-2 gene is the critical regulatory element involved in this positive feedback pathway. Thus, luteinization in some species appears to change specific gene transcription such that progesterone production becomes relatively independent of acute luteotrophic regulation and intraluteal PGF2alpha synthesis is induced by the second messenger pathways that are activated by PGF2alpha.

Animals↗

PubMed2002

Expression of DAZL protein in the human corpus luteum.

The DAZL gene and its homologues are required for the development of male and female germ cells in different species. However, their role in other aspects of human reproduction is not known. We have generated a polyclonal antibody to the DAZL protein and developed a sensitive standard curve quantitative-competitive-RT-PCR assay to characterize the expression of DAZL in the human corpus luteum (CL). DAZL transcripts are expressed in the CL, but the concentrations decreased with advancing luteal phase. In accordance with the mRNA data, DAZL protein was most abundant in the early phase CL. Immunohistochemical staining showed DAZL protein in the cytoplasm of granulosa-luteal cells. The distinct expression pattern of DAZL protein in the human CL may play an important role in the regulation of luteal function.

Animals↗

PubMed2001

Association study of the p53-gene Pro72Arg polymorphism in schizophrenia.

The p53 tumor-suppressor gene, encoding a phosphoprotein, is a key element in maintaining genomic stability and cell apoptosis. It is also implicated in nervous-system development. In order to examine the role of the p53 gene for the pathogenesis of schizophrenic disorders, patients (n=155) and control subjects (n=168) were genotyped for the p53-Pro72Arg polymorphism. The results demonstrated no association with schizophrenia and/or age of onset for this polymorphism.

Adult↗

PubMed2001

The upregulation of angiotensin II receptor AT(1) in human preeclamptic placenta.

The human placenta has been considered to possess a locally generated renin-angiotensin system (RAS), which may play a physiological role in the regulation of uteroplacental blood circulation. The changes in the expression of such a placental RAS during pregnancy could be important for the physiological and pathophysiological aspects of some clinical disorders, such as pregnancy-induced hypertension, preeclampsia. In the present study, the alterations of expression and localization of placental angiotensin II receptor subtypes, namely AT(1) in patients with preeclampsia (elective caesarean delivery) were investigated and compared with controls (vaginal delivery and elective caesarian delivery) using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry respectively. Results from RT-PCR analysis revealed an upregulated expression of placental mRNA for AT(1) receptor subtype in patients with preeclampsia when compared with those in controls. In addition, there was also a significant activation of placental expression of angiotensinogen mRNA in patients with preeclampsia. Results from Western blot showed that the expression of AT(1) receptor was also upregulated. Immunohistochemical results further demonstrated that increased immunoreactivity for placental AT(1) receptor was predominantly localized to the thin layers of syncytiotrophoblasts and, to a less extent, the capillaries of the term placental villi. These data indicate that upregulation of placental RAS components, notably AT(1) receptor in the syncytiotrophoblasts, could play a pathophysiological role in patients with preeclampsia.

Angiotensinogen↗

PubMed2001

Effects of Cordyceps sinensis on testosterone production in normal mouse Leydig cells.

The stimulatory effect of Cordyceps sinensis (CS) on MA-10 mouse Leydig tumor cell steroidogenesis was previously demonstrated in our laboratory. In the present studies, we further determined the effect of CS on steroidogenesis in purified normal mouse Leydig cells. Different concentrations of CS (0.1-10 mg/ml) were added to Leydig cells without or with human chorionic gonadotropin (hCG) (50 ng/ml), and the steroid production was determined by radioimmunoassay (RIA). The results illustrated that CS stimulated normal mouse Leydig cell steroidogenesis in a dose-dependent relationship. CS at 3 mg/ml significantly stimulated testosterone production (p<0.05). Concerning the temporal relationship, CS at 3 mg/ml stimulated maximal testosterone production between 2 to 3 hr. Interestingly, hCG-stimulated testosterone productions were suppressed by CS in a dose-dependent relationship. CS also reduced dbcAMP-stimulated testosterone productions, which indicated that CS affected signal transduction pathway of steroidogenesis after the formation of cyclic AMP. Moreover, cycloheximide inhibited CS-treated mouse Leydig cell testosterone production, suggesting that new protein synthesis was required for CS-stimulated steroidogenesis.

Animals↗

PubMed2001

Effect of diallyl sulfide and diallyl disulfide, the active principles of garlic, on the aflatoxin B(1)-induced DNA damage in primary rat hepatocytes.

The objective of this study was to investigate the effect of the active principles in garlic-- diallyl sulfide (DAS) and diallyl disulfide (DADS)--on aflatoxin B(1) (AFB(1))-induced DNA damage in primary rat hepatocytes. Primary rat hepatocytes, induced with DNA damage using 10 microM AFB(1) were used as an experimental model. According to the results of LDH leakage, 0.5 and 2 mM of DAS or 0.5 and 1 mM of DADS significantly increased the viability of hepatocytes compared with the AFB(1) controls after 4, 8 and 24 h treatment (P<0.05). According to the results of unscheduled DNA synthesis (UDS) test, 0.5 and 2 mM of DAS or 0.5 and 1 mM of DADS could significantly decrease the DNA damage induced by AFB(1) (P<0.05). Furthermore, 0.5 and 2 mM DAS or 0.5 and 1 mM DADS could increase the glutathione S-transferase (GST) and glutathione peroxidase (GPx) activities as compared with the AFB(1) controls after 24 h treatment (P<0.05). Results of immunoblot analysis of cytosolic GST isoenzyme indicate that the levels of GST isoform Ya, Yb2 and Yc were markedly increased after treatment with 0.5 and 2 mM DAS or 0.5 and 1 mM DADS compared with the AFB(1) control. These results indicate that 0.5 and 2 mM DAS or 0.5 and 1 mM DADS might protect hepatocytes from AFB(1)-induced DNA damage via increasing the activities of GST and GPx.

Aflatoxin B1↗

PubMed2001

Association between tryptophan hydroxylase gene polymorphism (A218C) and schizophrenic disorders.

The human tryptophan hydroxylase (TPH) gene, the rate-limiting enzyme in serotonin biosynthesis, was localized on human chromosome 11p14-p15.3. Variation within intron 7 of the TPH gene was found to influence serotonin metabolism in the brain. To explore the possible role of TPH in the pathogenesis of schizophrenic disorders, we genotyped the TPH A218C polymorphism in 196 schizophrenic patients and 251 controls. The results demonstrated that genotype distribution was significantly different between schizophrenic patients and control subjects (P=0.002). No association was found between TPH genotypes and suicidal history in schizophrenic patients (P=0.239). The positive finding in this study suggests that the TPH 218A allele is a risk factor for schizophrenic disorders or is in linkage disequilibrium with the putative schizophrenia susceptibility locus in Han Chinese population.

Acute Disease↗

PubMed2001

Association analysis of polymorphism in the promoter region of the alpha2a-adrenoceptor gene with schizophrenia and clozapine response.

There exists considerable evidence implicating the alpha (alpha) adrenergic system in the superior therapeutic effects of clozapine for the treatment of schizophrenia, as also its associated adverse hypersalivation side effect. It would seem plausible for variants of the adrenoceptors to be associated with the clozapine response. The present study tested the hypothesis that a biallelic polymorphism in the promoter region of the alpha2a-adrenoceptor gene confers susceptibility to schizophrenia, and is associated with a clozapine-induced (favorable) therapeutic response and/or a clozapine-induced hypersalivation. Ninety-seven treatment-resistant schizophrenic patients were assessed using the Brief Psychiatric Rating Scale before and after clozapine treatment. The results of clozapine treatment demonstrated that the alpha2a-adrenoceptor gene variants did not play a major role in the susceptibility, hypersalivation adverse effect or clozapine response of patients with schizophrenia. The polymorphism of the alpha2a-adrenoceptor gene investigated is not likely to play a major role in the pathogenesis of schizophrenic disorders or clozapine response, although the hypothesis that these genes are implicated in the cognitive deficit and polydipsia associated with schizophrenic disorders may, however, still warrant further study.

Adult↗

PubMed2001

Association study between cannabinoid receptor gene (CNR1) and pathogenesis and psychotic symptoms of mood disorders.

Cannabis can induce mood change and sometimes psychotic symptoms in normal persons. In brain, the main active ingredient of cannabis acts via the cannabinoid CB1 receptor (CNR1) which is located on chromosome 6q14-15. Linkage studies have suggested the presence of a bipolar disorder susceptibility locus on chromosome 6q. In this population based association study, we tested the hypothesis that a microsatellite polymorphism in the promoter region of the CNR1 gene confers susceptibility to mood disorders and psychotic features. We genotyped the CNR1 gene is 154 mood disorder patients and 165 normal controls. The results showed that the triplet repeat polymorphism in the promoter region of the CNR1 gene was not likely to be involved in the pathogenesis or in the psychotic symptoms of mood disorders.

Adult↗

PubMed2001

Allelic variants of the alpha1a adrenoceptor and the promoter region of the alpha2a adrenoceptor and temperament factors.

Human personality traits are partially determined by genes. It has been suggested that the reward-dependence dimension assessed by the Tridimensional Personality Questionnaire (TPQ) is related to the central noradrenergic system. Our population-based association study tested the hypothesis that genetic variants of the adrenoceptor are associated with this personality trait. The alpha1a- and the alpha2a-adrenoceptor genotypes were determined for 198 healthy Han Chinese who had completed the TPQ. We found no significant differences for TPQ personality-factor scores, including reward dependence and its subscales, for subjects showing different adrenoceptor genotypes. Our negative findings suggest that polymorphisms of the alpha1a adrenoceptor and of the promoter region of the alpha2a-adrenoceptor have no major effect on the reward-dependence personality trait as assessed by TPQ.

Adult↗

PubMed2001

Characteristics of Chinese suicide attempters admitted to a geropsychiatric unit.

PURPOSE: To investigate the characteristics for elderly Chinese suicide attempters in Taiwan and make comparisons with Western reports. METHODS: During a six-year period, patients admitted to a geropsychiatric unit as a result of a suicide attempt were investigated for factors related to the suicide attempt. RESULTS: Of the 722 admissions during this period, 55 (7.6%) were patients who had been admitted due to suicide attempt. The sex and age distributions for the suicide attempters were similar to those for other patients. The most common diagnoses were depressive disorders (56.4%), followed by delusional disorders (20.0%). A total of 121 suicide motives were cited for the 55 attempters, an average of 2.2 per person, with depressive symptoms commonly found on admission. During the first week of hospitalization, 53 attempters (96.4%) still exhibited suicidal ideation and six patients made a further suicide attempt, however, only three patients retained suicidal ideation on discharge. CONCLUSIONS: Our study confirms previous Western reports that depressive disorders are commonly manifested in elderly suicide attempters. There were differences in the motives and methods employed for the suicides, possibly due to cultural difference and/or sample source. Most of the suicide attempters exhibited a favourable response with hospitalization.

Age Factors↗

PubMed2001

A study of alpha-adrenoceptor gene polymorphisms and Alzheimer disease.

There exists considerable evidence implicating abnormalities of the alpha (alpha)-adrenergic system in the development of Alzheimer disease (AD). We propose to investigate potential correlations between the presence or otherwise of alpha-adrenoceptor polymorphisms and the presence of AD. We studied the polymorphisms of the alpha1a- and the alpha2a-adrenoceptor genes in 142 AD patients and 98 normal controls. The result demonstrated that none of the alpha2a-adrenoceptor genotypes was associated with increased susceptibility to AD. However, there was a trend that the frequency of the C allele of the alpha1a-adrenoceptor was elevated and an excess of the CC genotype (90.1%) was found in the subjects with AD in comparison with the controls (78.6%). This association was unrelated to the apolipoprotein E genotypes. The hypothesis that the alpha1a-adrenoceptor gene may be implicated in the pathogenesis of AD may deserve further study.

Aged↗

PubMed2001

Association study of nicotinic-receptor variants and major depressive disorder.

BACKGROUND: Depressive patients are more likely to smoke than the general population and nicotine was found to reduce the incidence and severity of depressive symptoms in many studies. These findings suggest that nicotinic acetylcholine receptors (nAChRs) may be implicated in major depressive disorder. We tested the hypothesis that the allelic variant, 2 bp deletion, of the partially duplicated alpha7 nAChR gene confers susceptibility to major depressive disorder. METHODS: We genotyped alpha7 nAChR in 72 patients with major depressive disorder and 103 normal controls. RESULTS: The distribution of the partially duplicated alpha7 nAChR genotypes (P=0.027) and alleles (P=0.037) suggests a modest difference between depressive patients and controls. LIMITATIONS: The -2 bp allele is thought to be present only in the duplicated exon 6, and the impact of the partially duplicated alpha7 nAChR and its -2 bp variant remain to be determined. CONCLUSIONS: The -2 bp allele of partially duplicated alpha7 nAChR may have an influence on the risk for development of major depressive disorder. The levels of significance achieved are modest and the findings must be replicated in other studies.

Adult↗

PubMed2001

Effects of organosulfur compounds from garlic oil on the antioxidation system in rat liver and red blood cells.

The modulation of garlic oil (GO) and three allyl compounds, diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS), on the antioxidation system in rat livers and red blood cells was examined. Rats were orally administered GO (200 mg/kg body weight), DAS (20, 80 mg/kg body weight), DADS (80 mg/kg body weight) or DATS (70 mg/kg body weight) three times a week for 6 weeks. Control rats received corn oil (2 ml/kg body weight) alone. GO, DADS and DATS treatment significantly increased the glutathione (GSH) content (48-84%) in red blood cells (P < 0.05). DATS displayed a greater enhancement than GO and DADS (P < 0.05). Hemolysis induced by tert-butyl hydroperoxide was not suppressed by GO or allyl compound treatment although higher GSH content was evident. Hepatic GSH was not influenced by garlic components. In rat livers, DADS and DATS significantly increased the activity of GSH reductase (46 and 54%, respectively) and of GSH S-transferase (GST) (63 and 103%, respectively), but decreased the GSH peroxidase activity (27 and 28%, respectively). In contrast, GSH reductase and GST activities in the DAS group, either 20 or 80 mg/kg body weight, were similar to the control group. A decrease of GSH peroxidase activity was observed in rats dosed with 80 mg/kg body weight (P < 0.05). An increase in GST activity and a decrease in GSH peroxidase activities were also noted in GO-treated rats (P < 0.05). In red blood cells, three GSH-related antioxidant enzyme activities were not affected by garlic oil and its organosulfur components. Immunoblot assay showed that, accompanying the increase in hepatic GST activity, GO, DADS, DAS (80 mg/kg body weight) and DATS increased the expression of GST Ya, Yb1 and Yc proteins. Results indicate that GO and three allyl compounds play a differential role in modulation of the GSH-related antioxidant system in rat livers and red blood cells.

Allyl Compounds↗